Borax bead test is given by :
The correct options are
B A cobalt salt
C A copper salt
D A nickelate salt
Borax bead test is a test for the presence of certain metals by observing the colours given to a bead of borax in a loop of platinum wire held in the oxidizing and redusing parts of a bunsen burner flame.
An aluminium salt gives colourless result(it dont give borax bead test)
A cobalt salt gives deep blue colour result
A copper salt gives sky blue and red colour in oxidizing and redusing parts respectively.
A nickelate salt gives yellow brown and greay colour in oxidizing and redusing parts respectively.
So only alluminium salt dont give borax bead test all the others gives borax bead test
Hence options B,C & D are correct.